EKU General Botany Lab
Water Molds and Simple Fungi
Oomycota, Chytridiomycota, Zygomycota
Saprolegnia (Oomycota)
antheridial
hyphae
oogonium with
eggs inside
vegetative hyphae
(2n and coenocytic)
Saprolegnia reproduction
Sexual
Asexual
(resistant zygote)
(Antheridia and antheridial hyphae are
basically interchangeable terms.)
Zoosporangium
Phlyctochytrium
a ‘holocarpic’
chytrid
mycelia
rhizoidal hyphae
Allomyces
resistant
sporangia
(meiosporangia)
a filamentous chytrid
coenocytic hyphae
mitosporangia
The true colors of this
organism have been
greatly distorted by the
technique used to make
the permanent slide from
which this photo was
taken. (See the next
slide.)
Is this the sporophyte (2n) phase, or the gametophyte (n) phase?
The last slide was of preserved material.
Here is a better slide--of living material.
photo by Ross Clark
This is the diploid (2n) phase of Allomyces. All of the sporangia in this photo
are resistant meiosporangia. No thin-walled mitosporangia are visible.
These resistant sporangia eventually will detach and float to the bottom. As spring
arrives, meiosis will occur inside the sporangia and they will release haploid (n) meiozoospores.
Allomyces gametangia
photo by Ross Clark
In Allomyces, the male and female gametangia usually occur in pairs, with one sex
above the other. In the picture above, you can see the brownish male gametangia above
the clear female gametangia. The female gametangia have already released their gametes.
The bright white spots are the exit papillae where the female gametes left the gametangia.
Rhizopus nigricans (Zygomycota)
Black Bread Mold
Sporangium
Sporangiophores
Spores
Columella
Rhizoids
Mycelium
(coenocytic)
Rhizopus nigricans reproduction
(Zygomycota)
suspensor
asexual phase
sexual phase
diploid
suspensor
Some chytrid pictures
chytrid on
diatom
a holcentric chytrid
More chytrids!
Polymyxa, a chytrid-like organism,
but not a chytrid (has 2 anterior
whiplash flagella)
Diagram of chytrid
zoospore; one posterior
whiplash flagellum
chytrids on spirogyra cell
Don’t forget – some chytrids, such
as Allomyces, have filamentous hyphae.